Voltage regulator



Nov. 1, 1927. 1,647,266

A. F. BROTZ VOLTAGE REGULATOR Fileq Aug. a, 1923 v Fig? /Z7 Z .5; 6Q 21 a 5 #2: 31 Vblt age Coll 14: Buckin Shunt C'ur rent GJil Fi d- 6 Bucking i Series Field ATTORNEY 25 vides the latter with Patented Nov. 1, 1927.

UNITED STATES 1,647,266 PATENT orrrcs. I

ANTON FRANK BBOTZ, F KOHLEB, WISCONSIN, ASSIGNOB 'IOTHE KOHLEB COMPANY,

01' KOHLER, WISCONSIN, A CORPORATION OF WISCONSIN.

VOLTAGE REGULATOR;

Application filed August 8, 1923. Serial No. 656,884.

This invention relates to regulators for generators designed to correspondingly vary the speed of the generator with the variations in the load to maintain an approximately constant voltage and one of the objects of the invention is to accomplish such voltage regulation by the combined influence of a throttle'controlling means and a field resistance controlling means without the spring adjustments of the former affecting the operation of the latter.

While the invention is not confined to any particular adaptation, it is especially appl1-' cable to internal combustion engine driven 1 farm lighting and power plants and serves to approximately proportion the fuel consumption to the actual load.

The present invention constitutes an improvement on, or a development of, the m- 2 vention covered by my United States patent for generator regulators No. 1,434,365, issued November 7, 1922, and my United States patent for regulators for generators, No. 1,47 2,7 88, issued November 6, 1923, and proindependent field remeans whereby the sistance regulating for the throttle control spring adjustments may be accomplished without affecting the gr operation of the field resistance regulating iheans, thus more efiectively avoiding the development of excessive voltage upon the sudden change from full load to mmimum 4 load conditions.

With this end in view the present invention' provides in addition to the regulating means for varying the speed of the generator with the load, a separate and independent automatically operated switch for introducing resistance in series with the shunt field when a predetermined voltage is attained.

Instead of regulating the voltage by maintaining a constant generator speed, a series field winding is used to buck or oppose the shunt field winding and thereby weaken the fieldstrength as the load increases, while automatic means simultaneously opens the throttle of the engine to-increase its speed. These two influences are so related that they maintain the voltage approximately com stant, but at times when the reduction in speed of the generator lags behind the reduction in load, a voltage coil sensitive to an abnormal increase in voltage and independent of the automatic throttle-operating means is now employed to operate a switch tags for weakening the shunt field of the generator by introducing resistance in series therewith and thus avoid the development of an excessive voltage. A

With the above and other objects in view the invention consists in the-Volta regulator as herein claimed and all equivalents.

Referring to the accompanying drawing, the figure constitutes a diagram of a voltage regulator for generators constructed in accordance with this invention...

In the drawing 10 indicates a generator driven by an internal combustion engine the throttle valve 11 of which is controlle by a solenoid having windings connected with the generator windings, as will be described. The generator as shown is of the shunt type and supplies the mains 12 containing lamps 13 or other translating devices.

The shunt field winding 14 of the generator 7 is opposed by a bucking series field winding 15 which becomes stronger as the load on the mains increases and thereby opposes a greater influence to the shunt field to weaken the field strength. At the same time a scrim coil 16, also in the load circuit and strengthened by the increasing load, opposes to a eater extent the influence of a shunt of voltage coil 17 to efiect a further opening movement of the throttle valve of the engine to increase the speed of the engine.

The solenoid is so constructed that the volcoil 17 of many turns of fine wire connected in parallel with the shunt field 14 and the current or series coil 16 of few turns of large wire in the load circuit together act upon the core 21 but in opposition to each other. The solenoid core is pivotally connected to the shorter arm of a bell crank lever 23. the other arm of which is connected by a link 27 with the throttle 11 so that in the extreme upper position of the core, as when the generator is not operating and the coils are therefore not energized the throttle is held in a partly closed position, as shown. The core is held in this position by an ad justable coil spring 25 which afi'ords a yielding resistance to the operation of the solenoid core. the adjustments of which determine the regulation.

When the generator is started with a minimum load or no load on the service mains. the series coil 16 opposes the voltage t e the generator.

the action of spring and will move the throttle to a position practically closing the intake manifold of the engine, so that the engine operates at a minimum speed under which the generator develops the line voltage. As the load increases the generator field is weakened by the bucking series field 15, as above mentioned, and the influence of the bucking current coil or series coil 16 becomes greater, tending to neutralize the infiuence of the voltage coil 17 and permitting the spring 25 to lift the core and move thethrottle toward its open position, thus increasing the supply of fuel to the engine to increase its speed corresponding with the increase in the load.

The full open position of the throttle 11 is attained under the condition of maximum load and should, for any reason, the current strength beincreased beyond this, as upon the occurrence of an overload, the further moyement of the throttle beyond its open position resulting therefrom will tend to slow down the engine. Also, with automatic starting control, the partially closed positionof the throttle for starting prevents the engine from racing before connecting the generator with the load, as is done when it is started with the throttle in full open position.

The proportioning of the field windings of the generator and of the coils of the solenoid and of the throttle and its operating means is made to compensate for a change in load by causing a change in speed without a material change in voltage developed by The weakening of the generator field by the bucking coil 15 serves to facilitate the increasing of the speed of the engine caused at the same time by the bucking influence of theseries coil 16 of the differential solenoid opening the throttle, and this bucking field winding exaggerates the speed variation characteristic of the'generator for constant voltage conditions so that the desired object is accomplished of materially reducing fuel consumption tocorrespond with a reduction of load.

As so far described the present invention is like that covered by my Patent 1,434,365 referred toand for the increased independent regulation a resistance is connected in series with the shunt field winding 14 of the generator and wires 31 and 32 connect the ends ofthis resistance with switch contacts 33 and 34 respectively of a resistance short circuiting switch operated by a sole- Hold which is connected across the terminals of the generator preferably with a resistance 51 in series therewith. Thus the field regulating resistance short circuit is controlled by a switch independent of the throttle controlling solenoid but sensitive to the variation in voltage developed by the generator. Being independent it is not affected by the spring adjustments of the solenoid core that are made for the purpose of controlling the operation of the throttle.

By means of this improvement the momentary rise in voltage when the load is suddenly reduced from full load to minimum load is, prevented, the sudden weakening of the bucking current coil 16 accompanied by a slight strengthening of the voltage coil 17 being sufiicient to cause the-core 21 to move to the position for closing the throttle. At the same time the'volt age coil 50, because of such momentary rise in voltage, opens the contacts 33 and34, thus breaking the short circuit around the regulating resistance 30 and including this resistance in the shunt field winding to weaken the fields and check the rise in voltage. Such tendency to abnormal voltage is only momentary and as soon as the speed of the generator has reduced to correspond with the new throttle position,

the normal conditions are restored, the throttle position being determined by the solenoid 1617 and the field resistance short circuiting switch being permitted to close by the voltage coil 50.

What I claim as new and desire to secure by Letters Patent is:

1. In a gas-engine-driven generator plant having a voltage regulator of the type wherein a solenoid-operated throttle increases the speed of the gas engine to correspond with an increase in the load on the mains, and having a generator with a shunt field; a voltage coil independent of the solenoid and connected with the generator terminals, a switch operated thereby, and an emergency resistance in series with the shunt field winding of the enerator and normally short-circuit: ed by t e switch.

2. In a gas-engine-operated generating system, the Qombination with means for automatically varying the speed of the engine with the load, means for adjusting the operation of the speed-varying means,'and an emergency protective device for preventing a surge of excessive voltage by suppressing the field excitation of the generator, compris ing a shunt field resistance, and independent introducing means therefor connected with the generator terminals to operate upon an excessive voltage.

Ill

3. In an internal-combustion-engine-driven generator system having means for varying the speed of the engine with the load, comprising an engine throttle sensitive to variations ofthe load, an adjustable spring for determining the operation of the throttle, a voltage coil connected with the generator terminals, a switch operated thereby, and a shunt field emergency resistance shortcircuited by said switch and operated independently of the throttle.

4. A generator having an armature and a shunt field, service mains connected across the armature, a series field opposed to the shunt field for voltage regulation, an engine having, driving connection with the generator, means dependent on the current flow through the service mains for varyingthe position of the throttle of the engine, and emergency means independent of the throttling means for avoidin an excessive voltage upon a sudden change rom full load to minimum load conditions comprising a voltage coil connected with the generator terminals,

and an emergency protective device, comprisopposing the shunt field to weaken the field as the load on the service mains increases and thereby obtain voltage regulation, a solenoid having its core connected with the throttle of the internal combustion engine, a voltage coil on the solenoid tending to move the throttle to its closed position, a current coil on the solenoid in series with the service mains and opposing the voltage coil for moving the throttle toward its open position as the load on the service mains increases, and an emergency protective device, comprising an independent voltage coil connected with the generator terminals, a switch operated thereby, and a shunt field resistance controlled by the switch for suppressing field excitation.

7. The combination with a gas-enginedriven generator having a shunt field winding and a bucking series field winding and a throttle control influenced in sympathy with the difi'erential action of the two field windings for voltage regulation by means of speed variation, an emergency protective device independent of the throttle control for preventing a surge of voltage upon the occurrence of a su den reduction of load during the time required for the reduction of generator speed to correspond with the reduced load comprising a voltage coil, a switch operated thereby, and a shunt field resistance controlled by the switch for suppressing field excitation.

- In testimony whereof I afiix my signature.

ANTON FRANK BROTZ 

